Rewiring the VIOFO TYPE-C HK4 HARDWIRE KIT

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Because I am particular about power, maybe too particular, I want to "adjust" the wiring on an Type-C HK4 kit when installing my A229 Pro main camera onto the
rear glass of the hatchback of an Outback. The length from fuse box to rear window glass is about 5,4 meters. The 20 AWG wire from the HK4 voltage drop will be about
1,1 vdc.

I would like to place the KH4 at the rear of the car, replace the 20 AWG with 18 AWG, run the power wire to the fuse box and have a drop of only ,711 vdc. I will then
shorten the USB side to the 1 or 2 meter length I need from the HK4 unit to the dashcam.

Doing this will ensure max vdc and amps to the dashcam, reduce interference from my BT air pressure sensors, and give me something to tinker with in my old age. :)

Any recommendations or considerations?
 
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On the 12 volt side, it does not matter if there is a voltage drop, since the voltage regulator in the HK4 will always output 5 volts anyway.
So if you want, you can shorten the HK4 12 volt cable, but there is no need to open the HK4, unsolder the current wire and solder on the new one, you can just crimp your new cable to a shortened old one.

On the USB side, shortening the cable will help, although Viofo have already tested that it works 100%, so the improvement is not necessary.

On your air pressure sensors, you may find that just coiling up the USB power cable is sufficient to solve the problem, maybe coil it and put it above the roof liner, well away from the pressure sensors.

Of course shortening the cables will save a little power, make the system more efficient, and give more recording time in parking mode, but I doubt that you will notice the difference...
 
If you want to keep it within spec the drop should be limited to 10% or 1.2 V DC from the 12 V battery (fully charged battery at rest is 12.6 V DC or +5%). You also have to consider the length of wire from the battery to the fuse panel and the loss at the fuse connection itself as both of these will increase the drop. You can measure the voltage at the fuse box to see what you are starting with. Also consider the voltage cutoff feature of the HK4 to prevent to battery from draining too low. You may need to reduce the cutoff voltage by a notch or two to compensate.

That being said how did you get 1.1 V DC drop on 18 ft of 20 AWG? I calculate only 0.4 V DC drop considering 20 AWG and 20 ft at 12 V DC and 1 amp load (10 W output @ 80% efficiency).
 
Nigel said:
On the 12 volt side, it does not matter if there is a voltage drop, since the voltage regulator in the HK4 will always output 5 volts anyway.
So if you want, you can shorten the HK4 12 volt cable, but there is no need to open the HK4, unsolder the current wire and solder on the new one, you can just crimp your new cable to a shortened old one.

On the USB side, shortening the cable will help, although Viofo have already tested that it works 100%, so the improvement is not necessary.

On your air pressure sensors, you may find that just coiling up the USB power cable is sufficient to solve the problem, maybe coil it and put it above the roof liner, well away from the pressure sensors.

Of course shortening the cables will save a little power, make the system more efficient, and give more recording time in parking mode, but I doubt that you will notice the difference...
Click to expand...

Thank you Nigel, I have considered crimping or soldering an extension to the existing power leads coming from the KH4 box, would be a bit simpler for certain and is likely the path I will take. I have about 40 years of using a soldering iron so I am good with one of those, honestly though, I think I would rather crimp and move on. I have no issue with coiling the extra USB cable into the headliner but I am concerned about the sunroof and the rearward factory satellite antenna.
 
dawilso9 said:
If you want to keep it within spec the drop should be limited to 10% or 1.2 V DC from the 12 V battery (fully charged battery at rest is 12.6 V DC or +5%). You also have to consider the length of wire from the battery to the fuse panel and the loss at the fuse connection itself as both of these will increase the drop. You can measure the voltage at the fuse box to see what you are starting with. Also consider the voltage cutoff feature of the HK4 to prevent to battery from draining too low. You may need to reduce the cutoff voltage by a notch or two to compensate.

That being said how did you get 1.1 V DC drop on 18 ft of 20 AWG? I calculate only 0.4 V DC drop considering 20 AWG and 20 ft at 12 V DC and 1 amp load (10 W output @ 80% efficiency).
Click to expand...

Figured with 3 amp draw, which is what I thought the dashcam would draw. I could well be mistaken on that figure though.
 
Augie said:
Figured with 3 amp draw, which is what I thought the dashcam would draw. I could well be mistaken on that figure though.
Click to expand...
The HK4 kit is only rated for 5 V/2 A output from the USB side. 2 A @ 5 V is 0.83 A @ 12 V. Of course you will have some losses on the buck converter so I round up to 1 A which is a very conservative 20% loss (most buck converters are above 90% efficient though).
 
Augie said:
I have about 40 years of using a soldering iron so I am good with one of those,
Click to expand...
In that case solder the join and protect it with some heat shrink tube, gives a much nicer and better join than crimp connectors. I still wouldn't bother opening up the HK4 case though.
 
I appreciated the advice and imput by everyone. I received my shipping notice about 50 minutes ago, with DHL doing the pickup in Hong Kong. The nearest DHL to me is
in South Carolina and I have had problems with them several years ago. I hope they have fixed their driver issue ( I exect they have ) or, hopefully the package is handed
off to another carrier.
 
Augie said:
I appreciated the advice and imput by everyone. I received my shipping notice about 50 minutes ago, with DHL doing the pickup in Hong Kong. The nearest DHL to me is
in South Carolina and I have had problems with them several years ago. I hope they have fixed their driver issue ( I exect they have ) or, hopefully the package is handed
off to another carrier.
Click to expand...
Not long now til it arrives for you hehe
 
Oh happy Monday. :) I received the 20/3 wire I ordered from Amazon,

National Wire and Cable

Pure copper and highly flexible, I ordered 25 feet / 7,62 meters and that should be enough. I will just solder/splice it into the original wires as suggested by Nigel. The outside of the cable measured 3,90mm across. Nice and small and will easily fit into anywhere it needs to go. I also received my 512 gb memory from Kingston today.
 
You going to put the converter unit behind a panel in the back? May want to make sure you can get to it relatively easily in case you need to adjust the cutoff voltage.
 
dawilso9 said:
You going to put the converter unit behind a panel in the back? May want to make sure you can get to it relatively easily in case you need to adjust the cutoff voltage.
Click to expand...


I have two options that seem reasonable. One is to use the sticky tape and place it on the rear window or on the trim. The other option is to place it in an open
storeage area in the left rear of the cargo area. There is an indentation, with a aux cig lighter power receptical, that I can place the converter next to.
 
Augie said:
Oh happy Monday. :) I received the 20/3 wire I ordered from Amazon,

National Wire and Cable

Pure copper and highly flexible, I ordered 25 feet / 7,62 meters and that should be enough. I will just solder/splice it into the original wires as suggested by Nigel. The outside of the cable measured 3,90mm across. Nice and small and will easily fit into anywhere it needs to go. I also received my 512 gb memory from Kingston today.
Click to expand...
Me too i have kingston 512gb same https://www.kingston.com/en/memory-cards/canvas-go-plus-microsd-card
 
The bitrate is not high enough to worry about needing high speed SD cards. The bigger point is the durability and write endurance at very high and low temps. You do not want to be in a situation where you need to get the footage from your cam only to find the SD card failed and the footage was lost or never recorded.
 
dawilso9 said:
The bitrate is not high enough to worry about needing high speed SD cards. The bigger point is the durability and write endurance at very high and low temps. You do not want to be in a situation where you need to get the footage from your cam only to find the SD card failed and the footage was lost or never recorded.
Click to expand...
Better if it doesn't reach those very high temperatures, so what you really want is an efficient, low power consumption card.
 
Nigel said:
Better if it doesn't reach those very high temperatures, so what you really want is an efficient, low power consumption card.
Click to expand...
Posted something about that the other week, with the new Samsung microSD cards announced the other month. Claimed they moved to a much more smaller process for the microcontroller, saying it should result in power savings. Part of me is intrigued.
 
Nigel said:
Better if it doesn't reach those very high temperatures, so what you really want is an efficient, low power consumption card.
Click to expand...
Sure, but you still want a card that is rated for constant writes.
 
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